One resident, who asked not to be named, said: “Everyone’s shocked. I heard about it when I came out to get some milk yesterday afternoon. I was really surprised, it’s horrific.

“It’s so sad.”

Another neighbour said: “I’m shocked, I never thought something like this would happen here.”

This afternoon part of Huskisson Street remained taped off with several police cars in place on the road and the adjacent alleyway,

Post morterms were due to be carried out on the couple today. Police said they would not be formally identifying the pair until after this had taken place.

The couple’s next-of-kin have been informed.

Emergency services were called to the street at around 10.40am yesterday by a worried passer-by who was “concerned for the safety” of the pair.

Merseyside Police said the bodies of a man in his 70s and woman in her 60s were found inside and, after “enquiries were undertaken”, a 46-year-old man was arrested on suspicion of their murders in the Rainhill area.

The force later confirmed the incident was believed to be domestic-related, adding they were not seeking anyone else in connection with the matter.